Opto-magnetic recording medium

Abstract

In an opto-magnetic recording medium having on a substrate at least a recording layer consisting of an amorphous magnetic material, there is provided between the substrate and the recording layer an undercoated layer comprising a silicon oxide film, a metal film and a nitride film laminated in succession from the substrate side.

We claim: 
     
       1. An opto-magnetic recording medium comprising: a plastic substrate at least substantially transparent to light;   a recording layer consisting of an amorphous magnetic material;   an under-coated layer comprising a silicon oxide film, a metal film at least substantially transparent to light and a nitride film laminated in succession from the substrate side between said substrate and said recording layer; and   a protective overcoat formed on the side of said recording layer opposite the side on which said under-coated layer is formed.   
     
     
       2. An opto-magnetic recording medium according to claim 1, wherein said recording layer is formed of GdTbFe or GdTbFeCo. 
     
     
       3. An opto-magnetic recording medium according to claim 1 wherein said protective overcoat is formed from a spacer layer, a reflecting film, a protective layer, an adhesive layer and a protective substrate which are laminated in succession from the recording layer side. 
     
     
       4. An opto-magnetic recording medium according to claim 1, wherein said silicon oxide film is formed of SiO 2  or SiO. 
     
     
       5. An opto-magnetic recording medium according to claim 1, wherein said metal film is formed of Si, Cr, Ni, Ti or Al. 
     
     
       6. An opto-magnetic recording medium according to claim 1, wherein said nitride film is formed of Si 3  N 4 , AlN or BN. 
     
     
       7. An opto-magnetic recording medium according to claim 4, wherein the thickness of said silicon oxide film is 500Å to 1000Å. 
     
     
       8. An opto-magnetic recording medium according to claim 5, wherein the thickness of said metal film is 20Å to 40Å. 
     
     
       9. An opto-magnetic recording medium according to claim 6, wherein the thickness of said nitride film is 200Å to 400Å.